<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <script>

        function fn(m, n) {
            if(n === 0) {
                return 1;
            }
            return fn(m, n- 1) * m;
        }
        var num = fn(2, 10);
        console.log(num);
    </script>
</head>
<body>
<style type="text/css">
    body{
        background-color: #00f\9;
        *background-color: #000000;
        -background-color: #f00;
    }
</style>
</body>
</html>